Phenol → Diphenyl carbonate

HRID 1895812Notes

Reaction equation

HRID 1895812 reaction equation
[OH-:1].[Na+].C(Cl)Cl.[C:6](Cl)(Cl)=[O:7].[C:10]1([OH:16])[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1>O>[C:6](=[O:7])([O:1][C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)[O:16][C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1

Participants

6

Reactant 4

HCID 996PhenolHCID 6344DichloromethaneHCID 6371PhosgeneHCID 14798Sodium Hydroxide5×

Product 1

HCID 7597Diphenyl carbonateYield 99.9%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
33 °C

Procedure

In a vertically upright cooled tubular reactor, a mixture of 145.2 kg/h of 14.5% strength sodium hydroxide solution produced by diluting 65.8 kg/h of a 32% strength sodium hydroxide solution with 79.4 kg/h of demineralized water, and 48.3 kg/h of phenol was continuously combined with a solution of 86.2 kg/h of methylene chloride and 27.5 kg/h of phosgene (8 mol % excess based on phenol). This reaction mixture was cooled to a temperature of 33° C. and after a median residence time of 15 seconds, a pH of 11.5 was measured. Then, in the second stage of the process, to this reaction mixture was added 5.4 kg/h of 50% strength NaOH, so that the pH of the second reaction stage, after a further residence time of 5 minutes, was 8.5. In the continuously operated reaction, metering fluctuations which occurred were contained by respective adaptations of the NaOH feeds. In the second stage of the process, the reaction mixture was constantly mixed by passing it through a tube provided with constrictions. The reaction temperature, after repeated addition of NaOH, was set to 30° C. by cooling. After separating off the organic phase from the aqueous phase (reaction wastewater), the DPC solution was washed with 0.6% strength hydrochloric acid and water. After removal of the solvent, 99.9% pure diphenyl carbonate was obtained. The reaction wastewater was combined with the wash phases and freed from solvent residues and catalyst by stripping with steam. After neutralization with hydrochloric acid and treatment with activated carbon, the production wastewater contained 13.2% by weight NaCl and less than 2 ppm of phenol.

Workup

  1. customproduced
  2. customafter a median residence time of 15 seconds
  3. customso that the pH of the second reaction stage
  4. customafter a further residence time of 5 minutes
  5. customIn the continuously operated reaction, metering fluctuations which
  6. additionIn the second stage of the process, the reaction mixture was constantly mixed
  7. customprovided with constrictions
  8. customwas set to 30° C.
  9. temperatureby cooling
  10. customAfter separating off the organic phase
  11. customfrom the aqueous phase (reaction wastewater)
  12. washthe DPC solution was washed with 0.6% strength hydrochloric acid and water
  13. customAfter removal of the solvent

Sources & evidence

ORD record
ord-2a553bf1121e4b0a93d3a92717dd3a98
Source dataset
uspto-grants-2013_08
Patent number
US08518231B2

Reaction notes

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